How Much Energy Do Building Energy Codes Really Save? Evidence from California

On the Freaknomics Radio podcast last week ( they interview Arik Levinson about his recent article "How Much Energy Do Building Energy Codes Really Save? Evidence from California".

Here is Levinson's abstract about the article (see attached articles). 

"Construction codes that regulate the energy efficiency of new buildings have been a centerpiece of US environmental policy for 40 years. California enacted the nation’s first energy building codes in 1978, and they were projected to reduce residential energy use—and associated pollution—by 80 percent. How effective have the building codes been? I take three approaches to answering that question. First, I compare current electricity use by California homes of different vintages constructed under different standards, controlling for home size, local weather, and tenant characteristics. Second, I examine how electricity in California homes varies with outdoor temperatures for buildings of different vintages. And third, I compare electricity use for buildings of different vintages in California, which has stringent building energy codes, to electricity use for buildings of different vintages in other states. All three approaches yield the same answer: there is no evidence that homes constructed since California instituted its building energy codes use less electricity today than homes built before the codes came into effect."

What do you all think?

Tags: Energy, codes, energy, savings

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According to the article the code standards did work but only enough to cover growth, not a net reduction.

My issue is that American Architecture is dumbed down to think you can be net-zero and not collect thermal energy, that's storing heat in winter, cold in summer at the right time of day or night.

If the sun is out most homes can use an active thermal collection system plugged into their ducting or a modern hot-water on the roof but that all needs a thermal-mass to store extra to use when the sun isn't there.

That's the essential message to me on "efficiency", if you don't collect it's all off the wire so steam power definitely involved and a huge carbon-footprint and you're buying it by-the-watt, as a machine shop that's a killer expense to profits.

The smaller windmills are a key issue to have mini-grids be base load reliable on solar-wind systems that are almost zero carbon-footprint compared to a steam plant and with modern batteries we can now use them quite easily [these are not lithium].

The battery-inverter arrays are in the pipeline for homes from Elon's recent announcement, my focus is a step up to mini-grid 35kw-100kw, this also has a few suppliers now and these make powering a small town's shops & restaurants possible.

Using more small windmills gains the order of magnitude more energy .... the gain is from having more of them per acre, the test windmill design is a bolt-together kit or DIY model and uses hand-wound coils.

The main point is to permit & install small ones is easy, the price tag each affordable in increments. The issue for small towns is paying for power by-the-watt

For a small shop that can be $30k/year, with solar-wind-battery it's around $1,300-$1,500/year for the same wattage, the difference then becomes profit and stays in town, this times all the small businesses and residents of the town.

So, for a small town in the coastal ranges they don't need the grid and will make way more cashflow per month investing in solar-wind-battery, there's plenty of wind power for the entire coast if you have solar panels as well.

This is a big deal to tourism, you can barely see tiny windmills 30ft tall from 1km away, they're too small, so the landscape will be missing the power lines ... horrible thought, eh? ... a coastal highway with no power lines in view.


"My issue is that American Architecture is dumbed down to think you can be net-zero and not collect thermal energy, that's storing heat in winter, cold in summer at the right time of day or night."

Perhaps you need to visit the DOE Zero Ready Homes,  or some of the AIA's sites on high performance residential buildings -- many architects do get it.  

I've seen and been around off grid systems,  and lots of small wind mills on farms.  The small wind mills often are replaced with electrical pumps running off the grid.

I've also spent quite a chunk of time the last three years looking at (conferences, technical sessions, papers, etc) at micro-grids  and looking at them.  They are not a slam dunk yet.

And I've had solar PV and thermal for going on six years -- and live just a few miles north of you in Kirkland.   I've had weather station above my house for nearly 30 years.  There isn't any type of wind turbine that would work (even if permitted by city and the HOA), that would have produce reliable power over the years.   Wind is location dependent.

You are over simplifying the issues and minimizing stuff that is being and has been done.

My issue with Arik Levinson's paper is that I believe he has also over simplified the problem, clumped stuff together and then picked the portions that would prove his point.

Some power companies are going to this business model, especially for large commercial accounts. Customer pays flat monthly rate based on available capacity, it's up to the customer to manage loads effectively. It's more of a grid capacity issue than power generation. Customers at that service level typically own their step-down transformers and buy power right off the main line.

I'm glad to see this discussion, difficult though it is. I see several points, to try to summarize...

1. A home's efficiency, let alone the efficiency of the overall lifestyle of the occupants, includes a lot more than electricity. Natural gas (possibly a bit lower due to codes); transportation (undoubtedly far higher due to more and larger cars and far more trips); food (probably larger due to long-distance transportation and refrigeration, eating higher on the food chain, energy-intensive agriculture, packaging); waste (increased consumption of goods, lots of packaging); and a generally richer lifestyle (larger homes by far, services delivered rather than done within the family, more entertainment devices, second homes, airplane travel, re-purchasing things that become rapidly obsolete, on and on). So the overall material and energy use of a family is way increased.

Limiting to only the efficiency of the house itself, I have seen another study that compared homes in southern California built in different decades and corrected for number of occupants and such, that also showed that the newer homes actually used more energy.

2. There are good things happening, e.g. improvements in specific appliances and of course building codes themselves. My home was built a century ago, and when I put insulation in the walls and attic, replaced the ancient furnace and plugged so many leaks that on our first blower test the blower couldn't even keep up (!!), it showed that in that era people just didn't think about these things at all! Needless to say our house uses a fraction of the energy now.

3. Even some new things we now use energy for are actually good -- the main example being my computer, which burns only about 30 watts but allows me to do most of my work in the world without needing to get into a car. I use hardly any paper, except for the piles of unsolicited junk mail we recycle every week. It should also be said that my life is a lot richer than my father's was, because I can be involved in many more things due to these technologies.

4. Our family has only bought one new car ever, but that was a 2011 Volt, which unquestionably lowers our footprint. The Volt's 40-mile electric range (even though it will switch to gas so we're never stranded) has improved my wife's driving habits because it's kind of a game to see if she can get everything done on electric, and it has good feedback to help her learn how to drive efficiently. Nonetheless she drives a lot because public transportation is all but unusable in our area.

The way I look at this, the problem is a culture of increased consumption (due to an economy that depends on growth, with every effort being made to increase my consumption rather than decrease it); a lack of feedback in the form of costs or even information as to what effect our actions have, and a dearth of community. Though I applaud aggressive codes and hold Art as a hero, the bigger picture is all about a culture in which consumption is rewarded, feedback is absent or incorrect, and people are isolated so that we substitute material and energy use for community, and constant activity for enjoyment of the people, culture and nature surrounding us. The changes needed go far deeper than regulations.


I think that critics and skeptics of efforts to improve energy efficiency in buildings are deluding themselves and others about the persistent problems of energy waste in buildings.  Building codes exist to help assure the public that buildings are built to accurate and accountable measures that provide assurance of performance of the buildings.

 However, like all reasonable laws, rules, and regulations, they are only as good as the people and institutions that enforce them. Unfortunately, in many areas building codes, rules, and regulations are not well monitored and enforced. 

I think building codes like those in California are very progressive and serve as models for other states, especially those who have weak energy efficiency codes.  (See state of Montana.)  Unfortunately we have those who profit from the US culture of waste.  We should all be working to improve building performance and have building rules and regulations that result in clear, unambiguous outcomes.

I think Art Levinson should investigate energy savings and the work on the building of the new, improved, and expanded beach home of Mitt Romney in California. Remember the Mitt Romney who ran for President.  We know he is “severely conservative.”  However, does his building plans show that he will build a home that has advanced energy efficiency features?  Will his new home use more energy than the older smaller home?

"Efficiency" to me and building methods boils down to this heat-transfer model run showing a standard wall, and the same wall with insulation board added outside the sheathing and furring to hold the siding off to allow condensation drip, three times more thermal resistance for the wall, far beyond the R-factor added of 9, mainly from killing conduction.

Essentially, sheetrock is a collector, studs conductors and nailing siding to sheathing a radiator in the standard wall, how can it conserve heat?

From this and others I've gone to no batt insulation wall design, pre-finished good plywood sheathing exposed to the interior and the studs also finished supplying shelving and extra space not needed thermally for a tiny home demo.

In a cold climate this is a radical improvement over the standard method using the same materials.

From these runs to me the preferred exterior is hemp-mortar as it adds thermal-mass, a thermal inertia along with enough insulation from the hemp shiv to improve results over than the insulation board, 4-times less loss than std, transmits moisture, fireproof, you can screw into it anywhere and absorbs CO2 over its lifetime for net-zero.

Wish me luck on permitting ...

Tom,  in our area  (Seattle) use something like Roxul for the exterior insulation... stay away from the XPS/EPS 

This is already mentioned in the comments, and it is not a bad thing to say it again.  In short, you have to measure energy use / sf.  And you have to take into consideration the typical appliances in homes then and now.  Having said that, we need to build even better.  Our thermal envelopes are still "bad" relative to what is possible.  Air sealing is still "bad" relative to what is possible.  We still have a lot of thermal bridging and need to pay attention to this.  In short, code is not good enough.  I have recently heard a quote - code = "the worst building that can be legally built"... And so many developers and production builders are still focused on simply meeting code. We need to improve the code more and more and more on each iteration.  So much more can be done with some attention to detail and higher performance products.  

The point I see in this is, we are using more energy in our homes and not less.  To reduce energy dependency as the number of homes go up we need to use less.  It does not matter that people keep buying more and plugging it in.  Bottom line as a nation at the end of the year we need to use less and not more.

I have retrofitted a 25 yr old home to Net Positive.  My energy bills were $25 per month when I installed my first solar electric system.  I have since air sealed, heavily insulated wall, windows, ceiling (that darn slab is left), air source heat pump, electric water heater, HRV (controlled ventilation), on demand circulation pump, larger solar electric (4.1kw), plugin electric hybrid car.  The load on my home on a hot summer day is less than my solar PV produces.  two years of 2000 excess kWh produced.  This year is a bit less because of the plug in car and more because of finishing the attic insulation.


We are not as sick as often, less allergy issues, less dusting, house is quitter (we never open windows and our air is fresher). As comfortable as we what to be (2-3 degrees or less "any time of the year" from the top to bottom, room to room in our 2 story home year round).

Future planned is a waste water heat recovery, reinstall my first reconditioned recalled 2.4 kW PV panels, install a rain water catchment even though our water usage is about 26 gal/ person per day.

I challenge all to do more to reduce your bills.

We as a society need to stop talk and start doing.


As an architect and energy consultant working in 14 states mainly those states which are deregulated. We have found that strict enforcement energy called and do not necessarily result in significant savings however when a homeowner takes a proactive approach in regards to relamping, window treatments and insulation upgrades there is a definite decrease in energy costs. However remember I said proactive. In addition in the deregulated states there are alternative gas and electric suppliers that can significantly guarantee and reduce both electricity and natural gas usage.
It certainly would be worth your while to look into this approach at 
and the free energy program offered at aresNRG

You may have already see this, but if not it is worthwhile. Forwarded from Rick Chitwood.


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